9d62deeb6f
Motivation: We can use the diamond operator these days. Modification: Use diamond operator whenever possible. Result: More modern code and less boiler-plate.
78 lines
3.2 KiB
Java
78 lines
3.2 KiB
Java
/*
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* Copyright 2018 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.resolver.dns;
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import io.netty.util.internal.SocketUtils;
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import io.netty.util.internal.logging.InternalLogger;
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import io.netty.util.internal.logging.InternalLoggerFactory;
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import javax.naming.Context;
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import javax.naming.NamingException;
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import javax.naming.directory.DirContext;
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import javax.naming.directory.InitialDirContext;
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import java.net.InetSocketAddress;
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import java.net.URI;
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import java.net.URISyntaxException;
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import java.util.Hashtable;
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import java.util.List;
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final class DirContextUtils {
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private static final InternalLogger logger =
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InternalLoggerFactory.getInstance(DirContextUtils.class);
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private DirContextUtils() { }
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static void addNameServers(List<InetSocketAddress> defaultNameServers, int defaultPort) {
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// Using jndi-dns to obtain the default name servers.
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//
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// See:
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// - http://docs.oracle.com/javase/8/docs/technotes/guides/jndi/jndi-dns.html
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// - http://mail.openjdk.java.net/pipermail/net-dev/2017-March/010695.html
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Hashtable<String, String> env = new Hashtable<>();
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env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.dns.DnsContextFactory");
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env.put("java.naming.provider.url", "dns://");
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try {
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DirContext ctx = new InitialDirContext(env);
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String dnsUrls = (String) ctx.getEnvironment().get("java.naming.provider.url");
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// Only try if not empty as otherwise we will produce an exception
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if (dnsUrls != null && !dnsUrls.isEmpty()) {
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String[] servers = dnsUrls.split(" ");
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for (String server : servers) {
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try {
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URI uri = new URI(server);
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String host = new URI(server).getHost();
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if (host == null || host.isEmpty()) {
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logger.debug(
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"Skipping a nameserver URI as host portion could not be extracted: {}", server);
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// If the host portion can not be parsed we should just skip this entry.
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continue;
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}
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int port = uri.getPort();
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defaultNameServers.add(SocketUtils.socketAddress(uri.getHost(), port == -1 ?
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defaultPort : port));
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} catch (URISyntaxException e) {
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logger.debug("Skipping a malformed nameserver URI: {}", server, e);
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}
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}
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}
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} catch (NamingException ignore) {
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// Will try reflection if this fails.
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}
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}
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}
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